Feeding management and production factors affecting goat milk composition and quality. I. Titratable...

Options Méditerranéennes, Series A, No. 74 219

Feeding management and production factors affecting goatmilk composition and quality. I. Titratable acidity and rennet-

coagulation

P. Superchi, A. Summer, A. Sabbioni, M. Malacarne, P. Franceschi and P. MarianiDipartimento di Produzioni Animali, Biotecnologie Veterinarie, Qualità e Sicurezza degli Alimenti

Università degli Studi di Parma, Italy

SUMMARY – Individual milk samples representing the overall morning milking were collected monthly (from Aprilto September) from 24 Saanen goats, uniformly distributed into two herds in Northern Italy, with the aim toevaluate the factors affecting titratable acidity and rennet-coagulation parameters. Herds differed in feedingmanagement system: "Traditional" and "Total Mixed Ration". Delivery date, parity number (primiparous orpluriparous), delivery type (single or twin) were considered. In correspondence of test days, lactation stage andmilk yield data were recorded. All milk samples were analysed for fat, protein, lactose, urea, somatic cells, pH,titratable acidity and rennet-coagulation parameters. Herd type significantly affected titratable acidity. Titratableacidity showed a positive relationship with milk yield and protein content and a negative one with pH. Milk fromprimiparous goats had a higher titratable acidity and a better clotting time. Milk from single delivery goats wascharacterised by a higher titratable acidity. Lower values of titratable acidity were accompanied by a worsening ofcurd firming time and curd firmness. Among rennet-coagulation parameters, herd type influenced only curdfirming time. An increase of protein content was related to a worse clotting time, a lower k20 and a higher a30. Anincrease of lactose content was related to an improvement of rennet-coagulation parameters. Curd firming timeworsening was related to increased somatic cells and pH; pH was also related to an increase of clotting time.

Keywords: Feeding management, production factors, titratable acidity, rennet-coagulation properties, goat milk.

RESUME – "Conduite alimentaire et facteurs de production infuençant la composition et la qualité du lait dechèvre. I. Acidité titrable et coagulation par présure". Des échantillons individuels de lait représentant la traiteentière du matin ont été prélevés (à partir d'avril jusqu’en septembre) sur 24 chèvres Saanen, uniformémentdistribuées en deux troupeaux situés dans le nord de l’Italie, dans le but d’évaluer les facteurs affectant l’aciditétitrable et les propriétés de coagulation. Les troupeaux étaient différents quant au régime d'alimentation :"traditionnel" et "ration complète". Le nombre de mises bas (primipares ou multipares), et le type de mise bas(simple ou double) ont été considérés. En correspondance des jours de prélèvement, le stade de lactation et lesdonnées de production laitière ont été enregistrées. Pour tous les échantillons ont été analysés gras, protéine,lactose, urée, cellules somatiques, pH, acidité titrable, et paramètres de coagulation. Les troupeaux influencentsignificativement l’acidité titrable. L'acidité titrable a montré une relation positive avec la production de lait et lateneur en protéines, et une relation négative avec le pH. Le lait des chèvres primipares a montré une aciditétitrable plus élevée et un meilleur temps de coagulation. Le lait des chèvres à mises bas simples s’est caractérisépar une acidité titrable plus élevée. Les valeurs plus basses d'acidité titrable ont été accompagnées d'unedétérioration du temps d’affermissement du caillé et de la fermeté du caillé. Le type de troupeau a influencé,parmi des paramètres de coagulation, seulement le temps d’affermissement du caillé. Une augmentation de lateneur en protéines a été liée à un plus mauvais temps de coagulation, un temps inférieur d’affermissement ducaillé et une fermeté plus élevée du caillé. Une augmentation de la teneur en lactose a été liée à uneamélioration des paramètres de coagulation. Un plus mauvais temps d’affermissement du caillé a été lié àl’augmentation des cellules somatiques et du pH; le pH a été lié également à une augmentation du temps decoagulation.

Mots-clés : Régime d’alimentation, facteurs de production, acidité titrable, propriétés de coagulation, lait dechèvre.

Introduction

Goat milk composition shows a marked variability, due to the breed and to the different climate andbreeding conditions (Jenness, 1980). The effects of lactation stage (Veinoglou et al., 1982;Castagnetti et al., 1984) and feeding and management factors (intensive or semi-intensive) (Haenlein,1980; Bailoni and Andrighetto, 1985; Pitti et al., 1988; Morand-Fehr et al., 1991; Sanz Sampelayo etal., 1999; Schmidely et al., 1999; Bava et al., 2001) were studied. Among production factors sampling

Options Méditerranéennes, Series A, No. 74224

References

Annibaldi, S., Ferri, G. and Mora, R. (1977). Nuovi orientamenti nella valutazione tecnica del latte:tipizzazione lattodinamografica. Sci. Tecn. Latt.-cas., 28: 115-126.

Anononymous (1963). Säuregradbestimmung nach Soxhlet-Henkel. Milchwissenschaft, 18: 520.Bailoni, L. and Andrighetto, I. (1995). Effetto del rapporto foraggi:concentrati sui parametri digestivo-

metabolici e sulle prestazioni produttive di capre primipare in lattazione. Zoot. Nutr. Anim., 21, 6:333-344.

Bava, L., Rapetti, L., Crovetto, G.M., Tambrini, A., Sandrucci, A., Galassi, G. and Succi, G. (2001).Effects of a nonforage diet on milk production, energy, and nitrogen metabolism in dairy goatsthroughout lactation. J. Dairy Sci., 84: 2450-2459.

Bhattacharya, A.N. (1980). Research on goat nutrition and management in Mediterranean MiddleEast and adjacent Arab Countries. J. Dairy Sci., 63: 1681-1700.

Biggs, D.A. (1978). Instrumental infrared estimation of fat, protein and lactose in milk: Collaborativestudy. J. Assoc. Off. Anal. Chem., 61: 1015-1034.

Brun-Bellut, J., Laurent, F. and Vignon, B. (1984). Taux d'ureé du lait, allantoine urinaire, temoins dela nutrition azoteé chez la chévre en lactation. Can. J. Anim. Sci., 64 (suppl.): 281-282.

Castagnetti, G.B., Chiavari, C. and Losi, G. (1984). Caratteristiche chimico-fisiche ed attitudinetecnologica del latte di razze caprine ad elevata potenzialità produttiva. Sci. Tecn. Latt-cas., 35:109-115.

Clark, S. and Sherbon, J.W. (2000). Alphas1-casein, milk composition and coagulation properties ofgoat milk. Small Ruminant Research, 38: 123-134.

Espie, W.E. and Mullan, W.M.A. (1990). Compositional aspects of goat milk in Northern Ireland.Milchwissenschaft, 45: 361-362.

Fantuz, F., Polidori, F., Cheli, F. and Baldi, A. (2001). Plasminogen activation system in goat milk andits relation with composition and coagulation properties. J. Dairy Sci., 84: 1786-1790.

Grandpierre, C., Ghisolfi, J. and Thouvenot, J.P. (1988). Etude biochimique du lait de chèvre. Cah.Nutr. Diét., 23: 367-373.

Grappin, R., Jeunet, R., Pillet, R. and Le Toquin, A. (1981). Etude des laits de chèvre. I. Teneur dulait de chèvre en matière grasse, matière azotée et fractions azotées. Le Lait, 61: 117-133.

Haenlein, G.F.W. (1980). Mineral nutrition of goats. J. Dairy Sci., 63: 1729-1748.Jenness, R. (1980). Composition and characteristics of goat milk: Review 1968-1979. J. Dairy Sci.,

63: 1605-1630.Leitner, G., Merin, U. and Silanikove, N. (2004). Changes in milk composition as affected by

subclinical mastitis in goats. J. Dairy Sci., 87: 1719-1726.Maraval, B. and Vignon, B. (1982). Mineral composition of goats’ milk in early lactation.

Milchwissenschaft, 37: 464-466.Mariani, P., Corriani, F., Fossa, E. and Pecorari, M. (1987). Composizione chimica, ripartizione delle

frazioni azotate e caratteristiche di coagulazione del latte di capra durante un ciclo di produzione.Sci. Tecn. Latt-cas., 38: 7-30.

Mariani, P., Zanzucchi, G., Bonatti, P. and Pecorari, M. (1990). Variazioni dell'acidità titolabile e dellecaratteristiche di coagulazione del latte in vacche frisone primipare e pluripare e rapporti con ilcontenuto di cellule somatiche. Annali Fac. Med. Vet., Univ. Parma, 10: 297-307.

Morand-Fehr, P., Bas, P., Blanchart, G., Daccord, R., Giger-Reverdin, S., Gihad, E.A.,Hadjipanayiotou, M., Mowlen, A., Remeuf, F. and Sauvant, D. (1991). Influence of feeding on goatmilk composition and technological characteritics. In: Goat Nutrition, Morand-Fehr, P. (ed.). Ed.Pudoc, Wageningen, The Netherlands, pp. 209-224.

Pecorari, M., Mariani, M.S., Calzolari, M.G. and Tedeschi, G. (1993). Il contenuto di urea nel latte:variazioni e rapporti con i parametri tecnologici. Sci. Tecn. Latt.-cas., 44: 144-154.

Piasentier, E., Valusso, R., Summer, A. and Mariani, P. (2000). Caratteristiche fisico-chimiche enutrizionali del latte misto di capre Camosciata, Saanen e meticce e della caciotta. Zoot. Nutr.Anim., 26: 263-274.

Pitti, A., Albano, E., Leotta, R., Taccini, F., Liponi, G.B., Colombani, B. and Orlandi, M. (1988).Variazioni del contenuto in Ca, P, Mg, Na, K, Fe, Cu e Zn nel latte di capra durante un periododella lattazione. Annali Facoltà di Medicina Veterinaria, Univ. Pisa, 41:163-173.

Remeuf, F., Lenoir, J. and Duby, C. (1989). Etude des relations entre le caractéristiques physico-chimiques des laits de chèvre et leur aptitude à la coagulation par la présure. Le Lait, 69: 499-518.

Sanz Sampelayo, M.R., Perez, M.L., Gil Extremera, F., Boza, J.J. and Boza, J. (1999). Use ofdifferent dietary protein sources for lactating goats: Milk production and composition as functionsof protein degradability and amino acid composition. J. Dairy Sci., 82: 555-565.


SAS (2002-2003). SAS/STAT User's Guide, ver. 9.1, SAS Institute Inc., Cary, NC, USA.Schmidely, P., Lloret-Pujol, M., Bas, P., Rouzeau, A. and Sauvant, D. (1999). Influence of feed intake

and source of dietry carbohydrate on milk yield and composition, nitrogen balance, and plasmaconstituents of lactating goats. J. Dairy Sci., 82: 747-755.

Schmidt-Madsen, P. (1975). Fluoro-opto-electronic cell-counting on milk. J. Dairy Res., 42: 227-239.Veinoglou, B., Baltadjieva, M., Kalatzopoulos, G., Stamenova, V. and Papadopoulou, E. (1982). La

composition du lait de chèvre de la region de Plovdiv en Bulgarie et de Ioannina en Grèce. Le Lait,62: 155-165.


month (Grappin et al., 1981; Mariani et al., 1987), parity number (Bhattacharya, 1980; Maraval andVignon, 1982), delivery month, single or twin delivery were considered. Remeuf et al. (1989) andClark and Sherbon (2000) studied the effects of feeding management and production factors on milkrennet-coagulation. The introduction of "Total mixed ration" ("TMR") in goat herds could lead to aimproving in milk quality. In this research the feeding management and production factors affectingtitratable acidity and rennet-coagulation Saanen goat milk have been studied.

Materials and methods

The study was carried out into 2 dairy goat herds, located in Alessandria province (Northern Italy),different for management, semi-intensive or intensive. In particular the two herds differed for feedingmanagement system: "Traditional" (hay, pasture, mixed feed, DMI 2.9 kg/d) and "TMR" (hay, mixedfeed, DMI 2.3 kg/d); the chemical composition of the two rations is reported in Table 1. In both herds agroup of 12 Saanen dairy goats was considered; the two groups were comparable for number of twindeliveries (17.39%) and for parity number (5 primiparous, 7 pluriparous). Lactation stage, at thebeginning of the research, was 50 ± 19 d. Individual goat milk samples, representing the morningmilking, were monthly collected (from April to September) from each goat.

Table 1. Chemical composition of the diet

Traditional Total mixed ration, TMR

Dry matter % 77.69 89.60Ash % DM 9.43 7.31Crude protein " 11.40 17.80Ether extract " 2.52 3.13Crude fibre " 27.90 22.25Starch " 18.19 24.26NDF " 54.66 42.35ADF " 38.54 26.07ADL " 6.03 5.38NPN % CP 18.28 24.05Soluble N % CP 38.44 28.86Milk FU % DM 72 80

Delivery date, parity number (primiparous or pluriparous) and delivery type (single or twin) wereconsidered. In correspondence of test days, lactation stage and milk yield data were recorded. Oneach milk sample the following analyses were carried out: fat, protein and lactose by means of midinfrared lectures with Milko-Scan 134A/B (Biggs, 1978); urea, by enzymatic reaction catalysed byurease (Pecorari et al., 1993) by means of Bun Analyzer apparatus; somatic cells, by fluoro-opto-metric method with Fossomatic 250 (Schmidt-Madsen, 1975); pH with a potentiometer; titratableacidity (°SH) with 0.25 N NaOH according to the Soxhlet-Henkel method (Anonymous, 1963) bymeans of the automatic titrator Crison Compact D; coagulation properties by means of Formagraph(Annibaldi et al., 1977): clotting time (r), curd firming time (k20), curd firmness measured 30 min afterrennet addition (a30). To the samples that did not coagulate into the technical time of analysis (30min), with the aim to obtain mean values representing the overall group of observations, wasarbitrarily attributed a value of 31 min to clotting time; the same value was attributed to curd firmingtime for milks that in 30 min of analysis did not reach a value finite of k20; for these latter the a30 valuewas assumed as zero mm (Mariani et al., 1990). Data were submitted to analysis of covariance (Fixedeffects: herd type; parity number; month of lactation; month of sampling; type of delivery; month ofdelivery. Covariates: milk yield, kg; fat, %; protein, %; lactose, %; somatic cells, 103/ml; pH; urea,mg/100 ml) by means of SAS statistical software (SAS, ver. 9.1, 2002-2003).


Results and discussion

Mean values and standard deviations

In Table 2 mean values and standard deviations for milk yield, fat, protein lactose, somatic cells,pH, urea, titratable acidity and rennet-coagulation parameters are reported. Few data are disposablein literature for rennet-coagulation properties. Fat content registered in this research is similar to datareported by Espie and Mullan (1990) and a little greater with respect to Grappin et al. (1981). Data inliterature, for protein and lactose, are variable (Jenness, 1980; Fantuz et al., 2001; Leitner et al.,2004), depending mostly on the breed and on the lactation stage; Grappin et al. (1981) report proteinvalues comparable with results of the present research. Our pH values are similar to Grandpierre etal. (1988). The registered somatic cell value corresponds to the value found by Castagnetti et al.(1984) and is lower than values observed by Piasentier et al. (2000); Leitner et al. (2004), for goatswith mammary gland infections, report values similar to our somatic cell data. Urea content measuredin this research is higher than values reported in literature (Grappin et al., 1981; Brun-Bellut et al.,1984); urea content, however, depends mostly from nutritional factors. Titratable acidity valuessubstantially agree with Castagnetti et al. (1984), while they are lower than those observed by Marianiet al. (1987) and higher than data reported by Piasentier et al. (2000). Titratable acidity is correlatedto the casein content, and for this reason the differences in literature are related to protein contentand, probably, to phosphorus content. Discordant values are registered in literature for rennet-coagulation properties, probably due to the different instruments and methodologies utilised.

Table 2. Production factors, titratable acidity and rennet-coagulation properties for the 2 diets. Meanand SD

Traditional TMR Total

Mean SD Mean SD Mean SD

Milk yield, kg 3.62 1.25 3.06 1.39 3.31 1.35Fat, % 3.49 1.11 3.70 1.31 3.61 1.22Protein, % 2.40 0.22 2.86 0.52 2.65 0.47Lactose, % 4.19 0.29 4.39 0.34 4.30 0.33SCC, x1000/ml 1451 1686 1849 2053 1672 1902pH 6.69 0.08 6.66 0.10 6.67 0.09Urea, mg/100 ml 42.12 7.55 49.61 11.65 46.27 10.67Titratable acidity, °SH/50 ml 2.54 0.33 2.94 0.41 2.76 0.42Clotting time, r, min 13.91 4.98 12.06 5.55 12.92 5.35Curd firming time, k20, min 7.51 6.55 4.78 3.25 16.32 12.98Curd firmness, a30, mm 17.96 8.91 23.31 9.90 20.81 9.79

Effects of feeding management and production factors on titratable acidity andrennet-coagulation properties

Herd type significantly affected titratable acidity (P<0.001), lower values being observed in the"Traditional" (Table 3). Titratable acidity showed a positive relationship with milk yield (b = 0.09;P<0.01) and milk protein content (b = 0.02; P<0.0001) and a negative relationship with pH (b = -3.6;P<0.0001). Milk from primiparous goats had a higher titratable acidity (P<0.001) and a better clottingtime (P<0.05). Milk from single delivery goats was characterised by a higher titratable acidity(P<0.05). Lower values of titratable acidity, observed for milk sampled in July (b = -0.31; P<0.01) andin August (b = -0.39; P<0.0001) with respect to September, were accompanied by a worsening ofcurd firming time (July: b = 13.51, August: b = 9.97; P<0.05) and of curd firmness (July: b = -11.40;P<0.01; August: b = -5.50; P<0.05). Herd type influenced, among rennet-coagulation parameters, onlycurd firming time (P<0.05), lower values being observed in the "Traditional". An increase of proteincontent was related to a worse clotting time (b = 4.8; P<0.001), a lower curd firming time (b = -8.7;P<0.05) and a higher curd firmness (b = 7.2; P<0.01). The improvement of curd firming time and curd


firmness is ready to explain, in fact, their correlation with the protein content is well known, while ismore difficult to explain the worsening of clotting time, probably due to a major effect of pH. Anincrease of lactose content was related to an improvement of rennet-coagulation parameters, i.e. alower clotting time (b = -10.48; P<0.0001), a lower curd firming time (b = -12.31; P<0.01), a highercurd firmness (b = 10.93; P<0.001). Curd firming time worsening was related to increased somaticcells (b = 0.002; P<0.05) and pH (b = 44.2; P<0.01); pH was related also to clotting time (b = 48.94;P<0.0001).

Conclusions

This study partially confirms the results reported in literature about the influence that productionfactors have on Saanen milk goat quality and, moreover, it evidences that the adoption of the TotalMixed Ration instead of the "Traditional" feeding technique improved the dairy-technological aptitudeof Saanen goat milk. This fact assumes a particular relevance, because most of goat milk is destinedto cheesemaking. The different titratable acidity for the two herds and the different rennet-coagulationproperties are probably related mainly to the different content of protein and mineral salts. The higherprotein content in the milk of TMR herd goats can be explained with the fact that these goats have ahigher protein intake (409.4 vs 330.6 g/d) with respect to the "Traditional" herd goats.

Acknowledgements

Research carried out with the financial contribute of MIUR (quote 60%). This paper must beattributed equally to authors.


References

Annibaldi, S., Ferri, G. and Mora, R. (1977). Nuovi orientamenti nella valutazione tecnica del latte:tipizzazione lattodinamografica. Sci. Tecn. Latt.-cas., 28: 115-126.

Anononymous (1963). Säuregradbestimmung nach Soxhlet-Henkel. Milchwissenschaft, 18: 520.Bailoni, L. and Andrighetto, I. (1995). Effetto del rapporto foraggi:concentrati sui parametri digestivo-

metabolici e sulle prestazioni produttive di capre primipare in lattazione. Zoot. Nutr. Anim., 21, 6:333-344.

Bava, L., Rapetti, L., Crovetto, G.M., Tambrini, A., Sandrucci, A., Galassi, G. and Succi, G. (2001).Effects of a nonforage diet on milk production, energy, and nitrogen metabolism in dairy goatsthroughout lactation. J. Dairy Sci., 84: 2450-2459.

Bhattacharya, A.N. (1980). Research on goat nutrition and management in Mediterranean MiddleEast and adjacent Arab Countries. J. Dairy Sci., 63: 1681-1700.

Biggs, D.A. (1978). Instrumental infrared estimation of fat, protein and lactose in milk: Collaborativestudy. J. Assoc. Off. Anal. Chem., 61: 1015-1034.

Brun-Bellut, J., Laurent, F. and Vignon, B. (1984). Taux d'ureé du lait, allantoine urinaire, temoins dela nutrition azoteé chez la chévre en lactation. Can. J. Anim. Sci., 64 (suppl.): 281-282.

Castagnetti, G.B., Chiavari, C. and Losi, G. (1984). Caratteristiche chimico-fisiche ed attitudinetecnologica del latte di razze caprine ad elevata potenzialità produttiva. Sci. Tecn. Latt-cas., 35:109-115.

Clark, S. and Sherbon, J.W. (2000). Alphas1-casein, milk composition and coagulation properties ofgoat milk. Small Ruminant Research, 38: 123-134.

Espie, W.E. and Mullan, W.M.A. (1990). Compositional aspects of goat milk in Northern Ireland.Milchwissenschaft, 45: 361-362.

Fantuz, F., Polidori, F., Cheli, F. and Baldi, A. (2001). Plasminogen activation system in goat milk andits relation with composition and coagulation properties. J. Dairy Sci., 84: 1786-1790.

Grandpierre, C., Ghisolfi, J. and Thouvenot, J.P. (1988). Etude biochimique du lait de chèvre. Cah.Nutr. Diét., 23: 367-373.

Grappin, R., Jeunet, R., Pillet, R. and Le Toquin, A. (1981). Etude des laits de chèvre. I. Teneur dulait de chèvre en matière grasse, matière azotée et fractions azotées. Le Lait, 61: 117-133.

Haenlein, G.F.W. (1980). Mineral nutrition of goats. J. Dairy Sci., 63: 1729-1748.Jenness, R. (1980). Composition and characteristics of goat milk: Review 1968-1979. J. Dairy Sci.,

63: 1605-1630.Leitner, G., Merin, U. and Silanikove, N. (2004). Changes in milk composition as affected by

subclinical mastitis in goats. J. Dairy Sci., 87: 1719-1726.Maraval, B. and Vignon, B. (1982). Mineral composition of goats’ milk in early lactation.

Milchwissenschaft, 37: 464-466.Mariani, P., Corriani, F., Fossa, E. and Pecorari, M. (1987). Composizione chimica, ripartizione delle

frazioni azotate e caratteristiche di coagulazione del latte di capra durante un ciclo di produzione.Sci. Tecn. Latt-cas., 38: 7-30.

Mariani, P., Zanzucchi, G., Bonatti, P. and Pecorari, M. (1990). Variazioni dell'acidità titolabile e dellecaratteristiche di coagulazione del latte in vacche frisone primipare e pluripare e rapporti con ilcontenuto di cellule somatiche. Annali Fac. Med. Vet., Univ. Parma, 10: 297-307.

Morand-Fehr, P., Bas, P., Blanchart, G., Daccord, R., Giger-Reverdin, S., Gihad, E.A.,Hadjipanayiotou, M., Mowlen, A., Remeuf, F. and Sauvant, D. (1991). Influence of feeding on goatmilk composition and technological characteritics. In: Goat Nutrition, Morand-Fehr, P. (ed.). Ed.Pudoc, Wageningen, The Netherlands, pp. 209-224.

Pecorari, M., Mariani, M.S., Calzolari, M.G. and Tedeschi, G. (1993). Il contenuto di urea nel latte:variazioni e rapporti con i parametri tecnologici. Sci. Tecn. Latt.-cas., 44: 144-154.

Piasentier, E., Valusso, R., Summer, A. and Mariani, P. (2000). Caratteristiche fisico-chimiche enutrizionali del latte misto di capre Camosciata, Saanen e meticce e della caciotta. Zoot. Nutr.Anim., 26: 263-274.

Pitti, A., Albano, E., Leotta, R., Taccini, F., Liponi, G.B., Colombani, B. and Orlandi, M. (1988).Variazioni del contenuto in Ca, P, Mg, Na, K, Fe, Cu e Zn nel latte di capra durante un periododella lattazione. Annali Facoltà di Medicina Veterinaria, Univ. Pisa, 41:163-173.

Remeuf, F., Lenoir, J. and Duby, C. (1989). Etude des relations entre le caractéristiques physico-chimiques des laits de chèvre et leur aptitude à la coagulation par la présure. Le Lait, 69: 499-518.

Sanz Sampelayo, M.R., Perez, M.L., Gil Extremera, F., Boza, J.J. and Boza, J. (1999). Use ofdifferent dietary protein sources for lactating goats: Milk production and composition as functionsof protein degradability and amino acid composition. J. Dairy Sci., 82: 555-565.


SAS (2002-2003). SAS/STAT User's Guide, ver. 9.1, SAS Institute Inc., Cary, NC, USA.Schmidely, P., Lloret-Pujol, M., Bas, P., Rouzeau, A. and Sauvant, D. (1999). Influence of feed intake

and source of dietry carbohydrate on milk yield and composition, nitrogen balance, and plasmaconstituents of lactating goats. J. Dairy Sci., 82: 747-755.

Schmidt-Madsen, P. (1975). Fluoro-opto-electronic cell-counting on milk. J. Dairy Res., 42: 227-239.Veinoglou, B., Baltadjieva, M., Kalatzopoulos, G., Stamenova, V. and Papadopoulou, E. (1982). La

composition du lait de chèvre de la region de Plovdiv en Bulgarie et de Ioannina en Grèce. Le Lait,62: 155-165.

Feeding management and production factors affecting goat milk composition and quality. I. Titratable...

Documents

Transcript of Feeding management and production factors affecting goat milk composition and quality. I. Titratable...